Self-propelled elevator systems, also referred to as ropeless elevator systems, are useful in certain applications (e.g., high rise buildings) where the mass of the ropes for a roped system is prohibitive and there is a desire for multiple elevator cars to travel in a single lane. There exist self-propelled elevator systems in which a first lane is designated for upward traveling elevator cars and a second lane is designated for downward traveling elevator cars under normal operating conditions. A transfer station at each end of the hoistway is used to move cars horizontally between the first lane and second lane. Additional lanes can also be supported.
One type of elevator propulsion system for ropeless elevator systems includes a linear motor, such as an electrically-controlled linear synchronous motor that uses at least one actively controlled winding. An accurate electrical angle determination is typically needed to efficiently operate a synchronous motor. Traditional elevator systems have relied upon rotary encoders or magnetic saliency of the motor to determine the electrical angle.